Factors that influence the cutaneous synthesis and dietary sources of vitamin D.
Level 5 - mechanism / opinion, no new human data
Bench food composition analysis combined with descriptive human and ex vivo UV exposure experiments.
PubMed 17254541 · doi:10.1016/j.abb.2006.12.017
What was done
The authors investigated factors influencing cutaneous vitamin D synthesis and dietary fish sources. They measured serum 25-hydroxyvitamin D levels in human volunteers with different skin types after repeated UV irradiation, evaluated previtamin D3 production in type II and type V human skin samples exposed to June noon sunlight, and quantified vitamin D content across commonly consumed oily and non-oily fish, specifically comparing farmed versus wild-caught Alaskan salmon.
What was found
Farmed salmon contained approximately 25% of the mean vitamin D content found in wild-caught Alaskan salmon, and vitamin D2 was present in farmed salmon but absent in wild-caught salmon. The abstract does not report numerical values, sample sizes, or statistical metrics for the human volunteer UV irradiation or the skin tissue model experiments.
Why it matters
This study highlights marked differences in dietary vitamin D content between wild and farmed fish sources, indicating farmed salmon provides significantly less vitamin D than wild-caught salmon.
Limits
The abstract omits sample sizes for human subjects, skin models, and fish batches. Quantitative findings, confidence intervals, and statistical tests are not reported for the cutaneous synthesis experiments.
Cited by
- supports Melanin acts as a natural sunscreen, requiring individuals with darker skin pigmentation to spend significantly more time in the sun to synthesize vitamin D.